Experimental and numerical study on the dissolution of alumina fine ceramics in CaO-SiO2-Al2O3-MgO slag

The dissolution of alumina fine ceramics in a CaO–SiO2–Al2O3–MgO slag was investigated at 1550 °C with a contemporary finger test apparatus. A computational model was constructed based on a diffusion-controlled dissolution mechanism and computational fluid dynamic simulations. Good agreement was found between the results of the static experiment and theoretical and simulation results. The dynamic experiments were well explained by the simulation model with the exception of the 200-rpm case. Microstructural investigations showed slag infiltration leading to the formation of a liquid phase surrounding corundum grains, that softened the material and facilitated erosion, thus explaining the discrepancies to the simulation results at higher speeds. Additionally, infiltration contributed to sample expansion, which was reflected in the reduction of observed Sherwood numbers for 50 rpm experiments. The influence of different convection sources on the dissolution rate was assessed through simulations, with good agreement observed between experimental and numerical findings.